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Message-Id: <2600955a0bd445bff17eb2bb43edbb71035ae2f5.1646422845.git.isaku.yamahata@intel.com>
Date: Fri, 4 Mar 2022 11:49:50 -0800
From: isaku.yamahata@...el.com
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: isaku.yamahata@...el.com, isaku.yamahata@...il.com,
Paolo Bonzini <pbonzini@...hat.com>,
Jim Mattson <jmattson@...gle.com>, erdemaktas@...gle.com,
Connor Kuehl <ckuehl@...hat.com>,
Sean Christopherson <seanjc@...gle.com>
Subject: [RFC PATCH v5 094/104] KVM: TDX: Handle TDX PV MMIO hypercall
From: Sean Christopherson <sean.j.christopherson@...el.com>
Export kvm_io_bus_read and kvm_mmio tracepoint and wire up TDX PV MMIO
hypercall to the KVM backend functions.
kvm_io_bus_read/write() searches KVM device emulated in kernel of the given
MMIO address and emulates the MMIO. As TDX PV MMIO also needs it, export
kvm_io_bus_read(). kvm_io_bus_write() is already exported. TDX PV MMIO
emulates some of MMIO itself. To add trace point consistently with x86
kvm, export kvm_mmio tracepoint.
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
arch/x86/kvm/vmx/tdx.c | 114 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 1 +
virt/kvm/kvm_main.c | 2 +
3 files changed, 117 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index c900347d0bc7..914af5da4805 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1012,6 +1012,118 @@ static int tdx_emulate_io(struct kvm_vcpu *vcpu)
return ret;
}
+static int tdx_complete_mmio(struct kvm_vcpu *vcpu)
+{
+ unsigned long val = 0;
+ gpa_t gpa;
+ int size;
+
+ WARN_ON(vcpu->mmio_needed != 1);
+ vcpu->mmio_needed = 0;
+
+ if (!vcpu->mmio_is_write) {
+ gpa = vcpu->mmio_fragments[0].gpa;
+ size = vcpu->mmio_fragments[0].len;
+
+ memcpy(&val, vcpu->run->mmio.data, size);
+ tdvmcall_set_return_val(vcpu, val);
+ trace_kvm_mmio(KVM_TRACE_MMIO_READ, size, gpa, &val);
+ }
+ return 1;
+}
+
+static inline int tdx_mmio_write(struct kvm_vcpu *vcpu, gpa_t gpa, int size,
+ unsigned long val)
+{
+ if (kvm_iodevice_write(vcpu, &vcpu->arch.apic->dev, gpa, size, &val) &&
+ kvm_io_bus_write(vcpu, KVM_MMIO_BUS, gpa, size, &val))
+ return -EOPNOTSUPP;
+
+ trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, size, gpa, &val);
+ return 0;
+}
+
+static inline int tdx_mmio_read(struct kvm_vcpu *vcpu, gpa_t gpa, int size)
+{
+ unsigned long val;
+
+ if (kvm_iodevice_read(vcpu, &vcpu->arch.apic->dev, gpa, size, &val) &&
+ kvm_io_bus_read(vcpu, KVM_MMIO_BUS, gpa, size, &val))
+ return -EOPNOTSUPP;
+
+ tdvmcall_set_return_val(vcpu, val);
+ trace_kvm_mmio(KVM_TRACE_MMIO_READ, size, gpa, &val);
+ return 0;
+}
+
+static int tdx_emulate_mmio(struct kvm_vcpu *vcpu)
+{
+ struct kvm_memory_slot *slot;
+ int size, write, r;
+ unsigned long val;
+ gpa_t gpa;
+
+ WARN_ON(vcpu->mmio_needed);
+
+ size = tdvmcall_p1_read(vcpu);
+ write = tdvmcall_p2_read(vcpu);
+ gpa = tdvmcall_p3_read(vcpu);
+ val = write ? tdvmcall_p4_read(vcpu) : 0;
+
+ if (size != 1 && size != 2 && size != 4 && size != 8)
+ goto error;
+ if (write != 0 && write != 1)
+ goto error;
+
+ /* Strip the shared bit, allow MMIO with and without it set. */
+ gpa = kvm_gpa_unalias(vcpu->kvm, gpa);
+
+ if (size > 8u || ((gpa + size - 1) ^ gpa) & PAGE_MASK)
+ goto error;
+
+ slot = kvm_vcpu_gfn_to_memslot(vcpu, gpa_to_gfn(gpa));
+ if (slot && !(slot->flags & KVM_MEMSLOT_INVALID))
+ goto error;
+
+ if (!kvm_io_bus_write(vcpu, KVM_FAST_MMIO_BUS, gpa, 0, NULL)) {
+ trace_kvm_fast_mmio(gpa);
+ return 1;
+ }
+
+ if (write)
+ r = tdx_mmio_write(vcpu, gpa, size, val);
+ else
+ r = tdx_mmio_read(vcpu, gpa, size);
+ if (!r) {
+ /* Kernel completed device emulation. */
+ tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
+ return 1;
+ }
+
+ /* Request the device emulation to userspace device model. */
+ vcpu->mmio_needed = 1;
+ vcpu->mmio_is_write = write;
+ vcpu->arch.complete_userspace_io = tdx_complete_mmio;
+
+ vcpu->run->mmio.phys_addr = gpa;
+ vcpu->run->mmio.len = size;
+ vcpu->run->mmio.is_write = write;
+ vcpu->run->exit_reason = KVM_EXIT_MMIO;
+
+ if (write) {
+ memcpy(vcpu->run->mmio.data, &val, size);
+ } else {
+ vcpu->mmio_fragments[0].gpa = gpa;
+ vcpu->mmio_fragments[0].len = size;
+ trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, size, gpa, NULL);
+ }
+ return 0;
+
+error:
+ tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
+ return 1;
+}
+
static int handle_tdvmcall(struct kvm_vcpu *vcpu)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
@@ -1029,6 +1141,8 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu)
return tdx_emulate_hlt(vcpu);
case EXIT_REASON_IO_INSTRUCTION:
return tdx_emulate_io(vcpu);
+ case EXIT_REASON_EPT_VIOLATION:
+ return tdx_emulate_mmio(vcpu);
default:
break;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9acb33a17445..483fa46b1be7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12915,6 +12915,7 @@ bool kvm_arch_dirty_log_supported(struct kvm *kvm)
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_entry);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_mmio);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d4e117f5b5b9..6db075db6098 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2259,6 +2259,7 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn
return NULL;
}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);
bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{
@@ -5126,6 +5127,7 @@ int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
r = __kvm_io_bus_read(vcpu, bus, &range, val);
return r < 0 ? r : 0;
}
+EXPORT_SYMBOL_GPL(kvm_io_bus_read);
/* Caller must hold slots_lock. */
int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
--
2.25.1
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